commonly known as FKFS
-The effect when a fat (or relatively large) kid thinks that playing the wii will make you fit.
-may cause sudden attempts (from that fat kid) of actually being athletic when clearly their are not.
'wow nathan tottaly has Fat kid 'fitness' sickness (FKFS) he tryed to flex for some girls because he stayed up all nightplaying wii fit
The feeling you get after making too many decisions and reading stupid definitions on the U.D. as an urban dictioary editor. Mostly the U.D. Editor Sickness gives you a stomach ache, head ache, and your feet get cold and sweaty. Sometimes you feel tired and your mouth tastes like stale Doritos. Could be cured by listening to "Down with the Sickness" by Disturbed and drinking water.
Turtle sickness is a result of sleeping too much or not getting out of bed until 2:00 or 3:00 pm. It is the feeling of still being tired even if you've slept for 10 or 12 hours. Your behavior and brain functions are noticably slowed down and reactionary time is also deminished.